Apparatus and method for producing respiration-related data

ABSTRACT

An apparatus for producing data concerning the respiration-related movements of the abdominal wall and/or the thorax of a person. The device comprises at least one first pair of sensor units ( 12, 14 ), which are configured for detachably fixing on the skin in an area of the person&#39;s thorax or abdomen, a first distance ( 1 ) apart; and a measuring device ( 20 ) which is connected to said first pair of sensor units and which is configured for detecting signals of the sensor units that can be evaluated electrically and for producing a distance signal corresponding to the first distance ( 1 ) and to changes in the same. Connected downstream of the measuring device is an evaluation device ( 22, 28 ) which is configured for evaluating pulsed and/or wave-shaped changes in the first distance signal, in such a way that periodical signal changes of a frequency in the range of 0.05 to 0.1 Hz are detected, distinguished from the periodical changes in the first distance signal that are due to the human heartbeat in terms of frequency, amplitude or signal shape and output in the form of a respiration display signal that can be displayed and further processed electronically.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of co-pending ApplicationSer. No. 10/380,723 which was filed on Jul. 16, 2003 entitled DEVICE ANDMETHOD FOR PRODUCING RESPIRATION-RELATED DATA.

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus and a method for producingmeasurement data concerning respiration-related movements of theabdominal wall and/or the thorax of a person. In particular, the presentinvention relates to a technical teaching the subject of which is thespecified detection and monitoring of the respiratory activity of aperson.

Breathing in (inspiration) is known to take place through expansion ofthe thoracic-pulmonary space by the respiratory muscles and through theresulting development of an alveolar partial vacuum in the expandinglung, leading to an inflow of air until pressure is equalized. Breathingout (expiration) takes place predominantly through a passive contractionof the thoracic space by a lowering of the thoracic cage and by anelasticity-related volumetric reduction (retraction) of the lung wherebyair flows out as a result of the production of relative alveolaroverpressure. Typical disorders of this human breathing process result,for example, from a reduction in lung elasticity or through narrowing ofthe apertures of the bronchial branches (restrictive or obstructiveventilation disorders), and from possible disorders of the respiratorycentre, of diffusion or blood circulation in the lung.

Diaphragmatic respiration is the component of respiration resulting fromcontraction of the diaphragm (approx. two-thirds of breathing volume).

Attempts to detect and measure a respiration-related expansion of thethoracic and abdominal area during respiration in humans are known fromthe prior art. Sensors used typically for this purpose operate onpiezoelectric principles and generate a comparatively low voltage as theoutput signal, a force being exerted on such a sensor through therespiration-related expansion of the thoracic or abdominal area during abreathing movement. By suitable processing a respiration signal isgenerated from a voltage signal produced thereby.

Other systems known from the prior art operate on an impedanceprinciple, i.e. by making use of suitable resistor elements theelectrical resistance of which changes through (respiration-related)movements of the thorax or the abdominal wall; in particular straingauges or suchlike sensors are used for this purpose.

Known approaches of this kind have, however, the disadvantage that onlya general detection of human breathing signals is possible, the qualityand resolution of the electronic signal obtained normally beinginsufficient to permit monitoring of further body parameters atacceptable cost and without separate, additional sensors.

In view, in particular, of an inherent biological connection betweenrespiration and cardiac activity it would therefore be desirable to beable to monitor both parameters simultaneously at low cost, and inparticular with the use of only one sensor or one sensor arrangement.The same applies to the movement or activity of the person, as could bedesirable in particular in the field of the observation of sportingactivities.

It is therefore the object of the present invention to provide anapparatus for generating measurement data concerning respiration-relatedmovements of the abdominal wall and/or the thorax of a person which isimproved with respect to signal resolution and measurement accuracy ingenerating a respiration display signal and which therefore also offers,in particular, possibilities of detecting from this respiration displaysignal further parameters or superposed signals, and creates thepossibility of generating with the same sensor system, in addition todata derived from respiratory movement, further data corresponding toother body parameters and functions, including heartbeat.

SUMMARY OF THE INVENTION

The foregoing object is achieved by an apparatus for generatingmeasurement data concerning respiration-related movements of theabdominal wall and/or the thorax of a person, comprising at least onefirst pair of sensor units which are configured for detachable fixing onthe skin on a thoracic or abdominal area of the person and are spacedapart by a first distance, and comprising a measuring device connectedto the first pair of sensor units and configured for detecting signalsof the sensor units which are capable of electrical evaluation and forgenerating a first distance signal corresponding to said first distanceand changes in same, wherein an evaluation unit is connected to theoutput of the measuring device and is so configured for evaluatingpulsed and/or waveform changes of the first distance signal thatperiodic signal changes of a frequency in the range between 0.05 and 0.1Hz can be detected, distinguished in terms of frequency, amplitude orsignal form from periodic changes of the first distance signal caused bythe human heartbeat and outputted as a respiration display signal whichcan be electronically displayed or further evaluated. The object isfurther achieved by a method comprising the steps of continuousmeasurement of a first distance between two first sensors attached onthe skin of the person on a thoracic or abdominal area, evaluation ofelectronic signal changes in the first measurement signal correspondingto changes in the first distance, and outputting of a respirationdisplay signal as a reaction to a periodical signal change in the rangebetween 0.1 and 0.5 Hz.

The present invention for data acquisition concerningrespiration-related movements of the abdominal wall and/or the thorax ofa person makes use in an inventively advantageous manner of theprinciple of data acquisition by measuring the distance between a pairof sensor units, changes in the distance between the sensors of the kindinduced by the respiration-related movements to be detected generatingthe first distance signal according to the invention, which can beappropriately evaluated. In this context the fixing of the sensors tothe skin is to be understood as a fixing of the sensors above the skinor body surface in such a way that a change in the distance between themcan be detected from a pair of measuring points; it is therefore alsoprovided in particular according to the invention to attach the sensorsto the skin via an intermediate layer—a garment, a fabric or the like.

This principle for generating the first distance signal corresponds tothat described in German Patent Application No. 42 14 523 and isrealized in a manner known as such by means of a transmitter-receiversystem based on ultrasonic or electromagnetic waves; with regard to anelectronic constructional implementation of the distance measurementmeans the above-mentioned Patent/Patent Application DE 42 14 523 is tobe regarded as included in its entirety in the present Application andas forming part of the invention.

The principle of ultrasonic distance measurement whereby the differencesin travel time of the ultrasonic signal between the sensor units aremeasured and evaluated has proved advantageous for the implementation ofmeasurement data generation concerning respiration-related movementsaccording to the invention; alternatively, it is possible to utilize andevaluate phase differences between the transmitted and received signal.

According to the present invention this known technology now findsapplication to the particular requirements of measuring arespiration-related movement of the abdominal wall and/or the thorax,the distance-dependent capture of measurement data relating to movementsof the thorax having proved to be especially reliable and accurate inconjunction with the evaluation unit provided according to theinvention. Advantageously, this procedure according to the invention notonly permits (general) testing for the presence of a breathing movement(which takes place according to the invention through the signal-relatedor time-related discrimination made possible by the evaluation unit),but the invention also offers the possibility—especially if a pluralityof pairs of sensors are provided according to a refinement of theinvention—of detecting with high resolution the thoracic movementsinduced by respiratory movements together with their temporal, local andspatial propagations, thereby making possible an investigation as towhether a respiratory process as such might possibly be pathological(if, for example, a detected, high-resolution form of the respirationsignal fails to correspond to a norm).

It has also been shown in the context of the invention that thesignal-form of normal breathing in the signal-time diagram issymmetrical, i.e. the rising and falling slopes of a breathing signalmeasured by distance change according to the invention are disposedsymmetrically with respect to a mean value. It is therefore preferred,according to a refinement of the invention, to associate with theevaluation unit signal-form detection means which, for discriminationfrom other signals (such as artifacts generated by sensor movement, bodyposition signals or cardiac motions) detect with high accuracy and lowsensitivity to interference the presence of respiratory activity andfurther improve display accuracy.

According to a further, preferred refinement (best mode) at least twopairs of sensor units are provided which, in a manner further preferred,in each case span intersecting distances (e.g. approximately at aright-angle) and irradiate the thorax or abdominal area. Therespiration-induced, locally (and in some cases temporarily) differentthoracic movements can be accounted for especially advantageously inthis way and evaluated for still more accurate measurement, e.g. bysummation or subtraction of the signals obtained from the two pairs ofsensors.

In addition, it is in general included within the present invention toalign the sensor units of a given pair of sensor units either in such away that a connecting line runs outside or along a periphery of thethorax and/or the abdominal area, or to cause the connecting line topass longitudinally or diagonally through the thorax and/or theabdominal area.

According to a preferred refinement of the invention it is provided, inaddition to the respiration-induced signal captured and outputtedaccording to the invention, to capture a heart rate signal of the personto be monitored, this being done in the context of the inventionlikewise by evaluation of the distance signal obtained through thedistance measurement according to the invention. As has advantageouslybeen shown, cardiac activity (having a frequency in a range of typicallyapprox. 1 Hz) also gives rise to periodic movements of the thorax,although the signals can, in the context of the invention, be reliablydiscriminated in terms of frequency and/or amplitude from the distancesignals characteristic of respiration. Additional active monitoring ofcardiac activity, in combination with respiration monitoring, thereforenot only makes it possible to increase, for example, the diagnosticvalue of the respiration signal itself, but also allows reliabledetection of further critical states of the person, such as sleep apneaor respiratory sinus arrhythmia, thereby allowing any requiredcounter-measures to be taken in good time. Advantageously, there is nonecessity for additional sensors for heartbeat detection which, inaddition to incurring equipment costs and causing potential problems infixing them to the patient, would present additional obstacles to acommon signal evaluation process using a respiration-dependent signal.

According to a further preferred refinement of the invention it isprovided that the first distance signal is evaluated to identify signalchanges caused by shocks such as those produced by walking, running orhopping of the person, which, as has been found in the context of thepresent invention, can also be reliably detected and discriminated fromthe respiration display signal (especially because, in the case oftypical step frequencies in the range of approx. 2.5 Hz, the signals canalready be reliably distinguished in their frequency range from thechanges in the first distance signal characteristic of breathing andcardiac activity). An additional, active monitoring of step frequencymade possible by this refinement of the invention therefore also permitsstates of the physical activity of the person, such as the trainingstate, and dependences between heart rate, respiration frequency andstep frequency, to be reliably detected and analyzed, and subsequentdiagnostic measures to be taken. If heart rate signals and stepfrequency signals are in the same range, they can be discriminated bydifferent amplitudes.

According to a further preferred refinement of the invention it hasemerged that a generating curve of an envelope of the respirationdisplay signal, and in particular the upper and lower limit values ofthis curve (which correspond to a maximum and a minimum distance betweenthe pair of sensor units), characteristically change when the personchanges his/her position, for example, in a sleep position—turning, forexample, from lying on their back to lying on their side. According to asuitable refinement, an evaluation of these generating curve parametersover a typical period of several minutes therefore additionally makes itpossible to derive position data relating to the person from thedistance signal.

The present invention is especially suited to use in conjunction with aportable unit co-operating with a base station for data transmissionwhich, an a manner further preferred, is effected wirelessly. Thepresent invention makes it possible to provide the units for dataacquisition and evaluation made available according to the invention,which are usually realized by means of suitably programmablecontrollers, in a portable, battery-powered housing which can be carriedabout continuously by the person monitored and which makes possiblepermanent monitoring of respiratory activity, the physical activity ofthe person and heart rate. Included here is the compilation of arespiration and stress profile (sleep, stress) and observation ofrespiration as a function of various parameters.

It should be clear that an instrument and a method are created by thepresent invention which are not only adapted rapidly to distinguishcritical from normal breathing states in a simply-evaluated and highlyreliable manner (therefore making it possible both to provide rapidassistance and to avoid superfluous dispensing of medication); inaddition, through a portable realization of the invention an extremelyadvantageous instrument for increasing flexibility and convenience inthe monitoring of respiratory activity is provided.

As is also achieved by the present invention, a combined analysis ofdifferent body functions including respiration, cardiac activity andphysical activity can be generated with simple means, and detailedstatements on the general condition of a monitored person can be made.

Further advantages, features and details of the invention are apparentfrom the following description of preferred embodiments with referenceto the drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the apparatus according to the inventionfor generating respiration-induced measurement data according to a firstembodiment of the invention as a block diagram showing the majorfunctional elements and their interaction;

FIG. 2 is a schematic illustration showing an anterior view of the bodyof a person with the apparatus according to FIG. 1 attached;

FIG. 3 is a posterior view according to FIG. 2;

FIGS. 4 to 9 are different schematic illustrations showing the fixing ofone or two pairs of sensor units and the definition of the firstdistance, in the form of pairs of schematic sectional views through theupper part of a human body showing the contracted and the expanded stateof the lung;

FIG. 10 is a signal/time diagram to clarify the first distance signaland its changes in a rest state;

FIG. 11 is an illustration according to FIG. 10, but while the person isrunning;

FIG. 12 shows the respiration display signal in enlarged time-resolutionto clarify superposed signals (person standing);

FIG. 13 is a representation analogous to FIG. 12 with the personhopping;

FIG. 14 is a representation analogous to FIGS. 10 to 13, but includingvarious respiration processes and a crossed sensor arrangement analogousto FIGS. 8, 9;

FIG. 15 is an enlarged illustration of a section of the right-handportion of the signal curve of FIG. 14;

FIG. 16 is a signal/time diagram to clarify the respiration displaysignal during sporting activity (skating); sensor arrangement accordingto FIG. 8, FIG. 9;

FIG. 17 is a signal/time diagram of a recording over approx. 50 minutesof measurement data for a sleeping person with change of the sleepingposition, and

FIG. 18 is an enlarged representation of a section of the view accordingto FIG. 17 showing the sleep display signal during sleep.

DETAILED DESCRIPTION

FIG. 1 clarifies in a block diagram the way in which two pairs of sensorunits 12, 14 and 16, 18 of an ultrasonic distance measuring unit 20 areassociated inside a portable housing 10, the ultrasonic distancemeasuring unit 20 emitting in an otherwise known manner—approximately asdescribed in Patent Application DE 42 14 523 referred to above—acorresponding signal suitable for further evaluation on the basis oftravel time differences during changes in a distance 1 (between sensorunits 12, 14) and a distance 3 (between sensor units 16, 18; inaddition, a third distance 2 between a sensor unit of the first pair anda sensor unit of the second pair is captured).

In concrete terms, as is shown in FIG. 1, an evaluation and outputtingunit 22 is connected to the output of the distance measuring unit 20 andgenerates the respiration display signal, which it sends to a displayunit 28, preferably a monitor, as a reaction to the distance measurementsignal (formed by summation or as a difference signal) of the unit 20 bysuitable frequency filtering (preferably effected by calculation fromthe signal curve) in the range of 0.1 to 0.5 Hz. The evaluation unit isconfigured for additionally generating a pulse display signal which isgenerated as a reaction to the detected changes in the first distancesignal caused in terms of frequency, amplitude and/or signal shape bythe human heartbeat, in particular, in a frequency range of between 0.8and 2.5 Hz.

In parallel thereto a digital signal pattern of the respiration displaysignal is stored for later evaluation or correlation with othermeasurement value curves in a memory unit 26, and a connection of therespiration monitor, as shown in FIG. 1 and realized in the simplestmanner, to a wirelessly-connected base station by means of atransmission antenna 30 takes place via a communication unit 24 shownonly schematically (and realized in practice, for example, by acurrently-used GSM mobile phone unit) for further monitoring andevaluation. The memory unit comprises analysis and storage meansassociated with the evaluation unit, which are configured forelectronically storing the respiration display signal and for detectinga change in terms of amplitude, frequency and/or signal form of therespiration display signal. The analysis and storage means areconfigured for generating a correlation signal between the respirationdisplay signal and the pulse display signal.

The measuring device and the evaluation unit are components of aportable battery-powered unit 10 which is connectable to a stationarybase unit by a wireless data connection for transmission of the displaysignal and/or further signals. The evaluation unit is configured foradditionally detecting a change in the first distance signal generatedby running or hopping of the person, and to determine a stepping orhopping frequency therefrom. Furthermore, the evaluation unit isconfigured for detecting a generating curve of the envelope of the firstdistance signal over a time interval which is long in comparison to abreathing frequency, and for determining a change in a lower and/orupper limit value of said generating curve.

FIGS. 2 and 3 show how the apparatus shown schematically in FIG. 1 isoperated in practice. A belt 40 is attached in the thoracic area to theschematically illustrated body of a patient, with which belt 40 both thehousing 10 and the four sensors 12 to 18 can be so attached to the bodyof the person that said sensors 12 to 18 can cooperate for reciprocaldistance measurement.

Referring now to FIGS. 4 to 9, a number of possible ways of attachingboth one and two pairs of sensor units to the body in the mannersketched in FIGS. 2, 3, so that signals well suited to evaluation areattainable, will be discussed by way of example below. In theillustrations of FIGS. 4 to 9 the sensors of one or two pairs of sensorunits are in each case represented as circles, and the arrows connectingthese circles mark the distances relevant to distance measurement or thegeneration of distance signals. The illustrations are horizontalcross-sections through the thoracic area at the level of the belt 40 inFIGS. 2, 3, a spinal column 42 being indicated schematically in theposterior area and the heart 44 in the left anterior area.

FIG. 4 clarifies schematically the fixing of only one pair of sensorunits jointly to an anterior thoracic area of the person so that thelength marking the distance (arrow 1) is located on the periphery of thebody. Whereas the contracted state of the thorax is shown in FIG. 4, thesensor units are attached in a corresponding manner in FIG. 5, but herethe thorax is expanded after inspiration.

FIGS. 6 and 7 (contracted and expanded state) clarify an alternativemanner of fixing a pair of sensors. In this case a first sensor of thepair is arranged in the anterior thoracic area and the second in theposterior area, so that the length (arrow 1) marking the distanceextends through the body. The increased distance between the sensorsachieved thereby makes it possible in some cases to achieve a furtherimproved resolution of the respiration-induced distance signal ascompared to the illustration in FIGS. 4, 5.

FIG. 8 shows a configuration having two pairs of sensor units which arearranged crosswise in the manner shown in the thoracic and back area; tothis extent the sensor arrangement in the sectional views according toFIG. 8, FIG. 9 (again in the contracted and expanded states) correspondsto the sensor arrangement shown in FIGS. 2 and 3 and to the designationof the distances 1, 2, 3 between the individual sensors according toFIG. 1. Here, use is also made of the fact that an additionalmeasurement distance 2 is formed between the sensor units 14 (of thefirst pair 12, 14) and 16 (of the second pair 16, 18), which can berealized in practice either by means of ultrasonic sensors having aplurality of sensor elements (crystals), by a plurality of sensors fixedin one place, or by a connection and evaluation such that in each caseone transmission element is always opposite one receiving element (forexample, in the illustration according to FIGS. 8 and 9, 12 could be atransmitting element and 14 a receiving element, 16 could again be atransmitting element and 18 a receiving element, so that atransmission-reception path for evaluation is also formed between 14 and16).

Through appropriate summation or subtraction an optimized signalresolution can be achieved, especially for the configuration shown inFIGS. 8, 9, which signal resolution, as will be discussed below withreference to signal curves, can be resolved into numerous parameters anddetailed information and evaluated in terms going beyond the simplepresence of respiration.

The representation in FIG. 10 shows a total of five breathing cycles,each breathing cycle being characterized by a rising slope 60, a maximumsignal area 62 and a descending slope 64, so that, independently of thedepth of breathing—the first two breathing cycles in the illustrationaccording to FIG. 10 represent normal cycles, the middle cycle is along, especially deep breathing cycle and the two breathing cycles onthe right are short, shallower breathing cycles—a symmetrical signalform is produced in the time domain (an axis of symmetry 66 is drawn forthe first signal as an example).

As compared to the illustration in FIG. 10, the diagram in FIG. 11,obtained while the person measured was running, shows a characteristicsuperposing of the respiration signal on a change signal in the range ofthe running frequency (approx. 2.5 Hz); the signals, which are shorterin comparison to the respiration cycle (although the latter isaccelerated by running) are denoted by reference numeral 66 in FIG. 11.

As is shown in FIG. 11, the present invention makes it possible not onlyto record the respiration signal during physical movement of the person(running,. hopping, etc.); because of the impacts occurring upon contactwith the ground a slight displacement of the sensor elements in therunning or hopping rhythm additionally occurs, these impact peaks beingclearly visible in FIG. 11. This superposed signal can, however, beeasily separated with regard to both frequency and amplitude from theunderlying respiration signal (in order to carry out a separateevaluation), and it also appears possible to transfer this evaluationconcept to other applications (cycling, in-line skating or the like)within the scope of the invention.

In the context of the embodiment described according to FIG. 1,evaluation of this stepping frequency is carried out by means of aseparate evaluation unit 34 which is associated with the evaluation anddisplay unit 28.

FIG. 12 shows in larger resolution in the signal-time diagram therespiration display signal of a standing person (analogous to FIG. 10);FIG. 13 corresponds with regard to resolution to FIG. 11 and showsrespiration display signals when hopping. Superpositions 66 induced bythe impacts are again clearly seen.

FIG. 14 illustrates a respiration display signal using a sensorarrangement (as in FIGS. 6, 7 and FIGS. 8, 9) in which the effectivedistance between a pair of sensor units is maximized to improve signalresolution. With his improved resolution the depth of breathing, inparticular, can be recognized and distinguished. Thus, the breathingcycles located on the left in FIG. 14 show a waveform characteristic ofdeep breathing; the following, signal-free time interval corresponds tothe pause in breathing after expiration, the following two signals oflower height correspond to normal (less deep) breathing, and theextended and high signal pulse located on the right corresponds to adeep inspiration and subsequent holding of the breath.

FIG. 15, which shows an enlargement of a section of the deep andsustained breathing cycle located on the right in FIG. 14, clarifies howsuperposed heartbeat pulses 68 are recognizable in the signal and can beadditionally detected and evaluated by suitable discrimination offrequency and/or amplitude. For this purpose a separate discriminationand evaluation unit 32, which detects heart rate in a manner known assuch by (preferably numerical) evaluation of a signal curve as in FIG.15, is associated with the evaluation and outputting unit 22 in FIG. 1.

FIG. 16 shows a further example of a respiration display signal duringsporting activity (here: skating), while FIG. 17 (long-time measurementover approx. 50 minutes) and FIG. 18 (resolution from FIG. 17 inindividual respiration cycles) illustrate breathing signals of a personwhile asleep.

As has been interestingly shown by (preferably numerical) evaluation ofthe envelope-generating curve over a period of several minutes accordingto FIG. 17, position changes of the sleeper (e.g. turning from the backto the side position) give rise to a characteristic jump (referencenumeral 70 in FIG. 17) in the envelope-generating curve of therespiration display signal or, more precisely, cause the minimumdistance to change abruptly and permanently. Accordingly, throughappropriate (preferably numerical) evaluation of the envelope-generatingcurve such a position change of the sleeper can be detected from thedistance signal, which is present in any case, and can be included infurther evaluations as a basis for diagnostic purposes.

It can be seen from a consideration of the examples of embodiments andapplications, therefore, that the present invention offers potential fora large number of possible applications; these extend from long-timerespiration measurement and long-time activity measurement through ataking account of respiration, pulse and movement data in biofeedbackand in stress management, through controlled breathing exercises forpregnant women, pace counting while jogging, monitoring of respirationdisorders of the most diverse kinds (including monitoring of SIDS,sudden infant death syndrome) to the identification of circulationparameters under stress (including energy conversion measurement), suchas the pulse-respiration quotient, all of which is achieved through theevaluation of a single distance signal, admittedly of high-resolutionand therefore highly informative, obtained according to the presentinvention. In addition to the frequency and depth of breathing (where aconnection with pulmonary volume exists), therefore, respirationvariability can also be detected as a determinable value; throughsuitable positioning of the sensor units differences between theefficiency of the right and left pulmonary lobes, differences betweendiurnal and nocturnal activities with regard to breathing, pulse, etc.,position changes during sleep, stepping frequency and heart rate (inorder to deduce the energy conversion of the person from a combinationof breathing and heart rate) and a relationship between abdominalbreathing and thoracic breathing, can likewise be detected asdeterminable values.

1-14. (canceled)
 15. An apparatus for generating measurement dataconcerning respiration-related movements of the abdominal wall and/orthe thorax of a person, comprising at least one first pair of sensorunits which are on an intermediate layer at a first distance from eachother when the intermediate layer is fixed on the skin on a thoracic orabdominal area of the person, a measuring device connected to the firstpair of sensor units and configured for detecting signals of the sensorunits which are capable of electrical evaluation and for generating afirst distance signal corresponding to said first distance and changesin same to a second distance signal corresponding to the changes indistances between the sensors as a result of respiratory relatedmovements of the person, the measuring device includes means foroutputting the first distance signal in the frequency range ofrespiration, an evaluation unit is connected to the output of themeasuring device and is so configured for evaluating pulsed and/orwaveform changes of the first distance signal that periodic signalchanges of a frequency in the range between 0.5 and 0.1 Hz can bedetected, distinguished in terms of frequency, amplitude or signal formfrom periodic changes of the first distance signal to the seconddistance signal caused by the human heartbeat and outputted as arespiration display signal which can be electronically displayed orfurther evaluated and wherein the evaluation unit is configured fordetecting an envelope curve of the first distance signal over a timeinterval which is long in comparison to a breathing frequency, and fordetermining a change in a lower and/or upper limit value of saidgenerating curve.
 16. An apparatus according to claim 15, wherein theevaluation unit includes means for detecting a signal form of change inthe first distance signal, the signal form detecting means being soconfigured that the respiration display signal is outputted only as areaction to a signal form of change which is symmetrical in time.
 17. Anapparatus according to claim 15 or 16, wherein at least one second pairof sensor units connected to the measuring device and configured fordetachable fixing on the skin on the thoracic or abdominal area of theperson and spaced apart by a second distance.
 18. An apparatus accordingto claim 17, wherein the evaluation unit is configured for summation orsubtraction of the first distance signal with respect to a seconddistance signal outputted by a second pair of sensor units.
 19. Anapparatus according to one of claims 15, 16 and 17, wherein theevaluation unit is configured for additionally generating a pulsedisplay signal which is generated as a reaction to the detected changesin the first distance signal caused in terms of frequency, amplitudeand/or signal shape by the human heartbeat, in a frequency range between0.8 and 2.5 Hz.
 20. An apparatus according to claim 19, wherein analysisand storage means associated with the evaluation unit, which areconfigured for electronically storing the respiration display signal andfor detecting a change in terms of amplitude, frequency and/or signalform of the respiration display signal.
 21. An apparatus according toclaim 20, wherein the analysis and storage means are configured forgenerating a correlation signal between the respiration display signaland a pulse display signal.
 22. An apparatus according to claim 15,wherein the measuring device and the evaluation unit are components of aportable, battery-powered unit which is connectable to a stationary baseunit by a wireless data connection for transmission of the displaysignal and/or further signals.
 23. An apparatus according claim 22,wherein the evaluation unit is configured for additionally detecting achange in the first distance signal generated by running or hopping ofthe person, and to determine a stepping or hopping frequency therefrom.24. An apparatus according claim 15, wherein the sensor units take theform of ultrasonic sensors.
 25. An apparatus for generating measurementdata concerning respiration-related movements of the abdominal walland/or the thorax of a person, comprising at least one first pair ofsensor units which are configured for detachable fixing on the skin on athoracic or abdominal area of the person and are spaced apart by a firstdistance, and comprising a measuring device connected to the first pairof sensor units and configured for detecting signals of the sensor unitswhich are capable of electrical evaluation and for generating a firstdistance signal corresponding to said first distance and changes insame, the measuring device includes means for outputting the firstdistance signal in the frequency range of respiration, an evaluationunit is connected to the output of the measuring device and is soconfigured for evaluating pulsed and/or waveform changes of the firstdistance signal that periodic signal changes of a frequency in the rangebetween 0.5 and 0.1 Hz can be detected, distinguished in terms offrequency, amplitude or signal form from periodic changes of the firstdistance signal caused by the human heartbeat and outputted as arespiration display signal which can be electronically displayed orfurther evaluated wherein the evaluation unit includes means fordetecting a signal form of change in the first distance signal, thesignal form detecting means being so configured that the respirationdisplay signal is outputted only as a reaction to a signal form ofchange which is symmetrical in a time domain, and wherein the sensorunits take the form of ultrasonic sensors.
 26. An apparatus according toclaim 25, wherein at least one second pair of sensor units connected tothe measuring device and configured for detachable fixing on the skin onthe thoracic or abdominal area of the person and spaced apart by asecond distance.
 27. An apparatus according to claim 26, wherein theevaluation unit is configured for summation or subtraction of the firstdistance signal with respect to a second distance signal outputted by asecond pair of sensor units.
 28. An apparatus according to claim 25,wherein the evaluation unit is configured for additionally generating apulse display signal which is generated as a reaction to the detectedchanges in the first distance signal caused in terms of frequency,amplitude and/or signal shape by the human heartbeat, in a frequencyrange between 0.8 and 2.5 Hz.
 29. An apparatus according to claim 28,wherein analysis and storage means associated with the evaluation unitare configured for electronically storing the respiration display signaland for detecting a change in terms of amplitude, frequency and/orsignal form of the respiration display signal.
 30. An apparatusaccording to claim 29, wherein the analysis and storage means areconfigured for generating a correlation signal between the respirationdisplay signal and a pulse display signal.
 31. An apparatus according toclaim 25, wherein the measuring device and the evaluation unit arecomponents of a portable battery-powered unit which is preferablyconnectable to a stationary base unit by means of a wireless dataconnection for transmission of the display signal and/or furthersignals.
 32. An apparatus according claim 25, wherein the evaluationunit is configured for additionally detecting a change in the firstdistance signal generated by running or hopping of the person, and todetermine a stepping or hopping frequency therefrom.
 33. An apparatusaccording to claim 25, wherein the evaluation unit is configured fordetecting a generating curve of the envelope of the first distancesignal over a time interval which is long in comparison to a breathingfrequency, and for determining a change in a lower and/or upper limitvalue of said generating curve.